An apparatus for providing image data in an image system includes: a stereoscopic image generation unit configured to receive image data and depth information data and generate stereoscopic image data; a parallax calculation unit configured to analyze parallax information of a 3D image from the stereoscopic image data, divide the analyzed parallax information step by step, and determine parallax step information; a caption and text generation unit configured to generate a caption and a text by applying the parallax step information and generate position information of the generated caption and text; and an image synthesis unit configured to insert the caption and text into the stereoscopic image data based on the position information of the caption and text and provide 3D image data.